Sleeping With One Eye Open
There’s an old saying that if you think you’re in danger, you might ought to sleep with one eye open.
Well it turns out that many kinds of birds do just that.
A group of scientists at Indiana State University studied mallard ducks to learn more about this trait. They filmed a row of ducks while they were sleeping. Sure enough they found that a good part of the time the ducks at the ends of the row kept the eye facing away from the group open, while the eye toward the other ducks closed in sleep. The ducks within the row were more likely to close both of their eyes to sleep.
The ducks at the ends of the line were actually controlling which side of the brain stayed awake, and which dozed. They were engaging in what scientists call single-hemisphere sleep. The eye controlled by the sleeping side of the brain closed, while the active side kept its eye open and on the lookout.
You can see how this is good for the group and for the lookout duck as well. The group gets the protection from having someone pulling guard duty, while the guard duck is at least able to get some rest.
睜一只眼睡覺
有個很老的說法，如果你覺得自己處于危險之中，你會睜著一只眼睡覺。
事實證明許多鳥類確實如此。
印第安納州立大學(xué)的一群科學(xué)家通過研究野鴨，對它們這個習(xí)性有了更多的了解。科學(xué)家們在鴨子們睡覺時進(jìn)行拍攝。果然，他們發(fā)現(xiàn)隊伍兩端的鴨子朝外的那只眼睛長時間睜著，而朝向其它鴨子的那只眼睛閉著睡覺。在隊列中間的鴨子們則雙眼緊閉睡覺。
隊列兩端的鴨子實際上在控制哪邊的大腦保持清醒與休息。它們處于科學(xué)家們所稱的單邊睡眠的狀態(tài)。被睡眠狀態(tài)大腦控制的眼睛閉上，而被運轉(zhuǎn)狀態(tài)大腦控制的眼睛睜開放哨。
這種習(xí)性對整個群體及放哨鴨子非常有益。鴨群通過一些鴨子放哨獲得保護(hù)，而同時放哨鴨子至少能得到一些休息。
